Found: Obscure 70s Scifi about cat-like creatures Sithi on planet Irya

I read this book in the late 90s but I believe it to have been published in the 70s.

I entered everything I could remember about the book into AI and it came up with this remarkably accurate summary that it had pieced together from collector's notes. It suggested it may be a lost Mildred Broxon book, but that doesn't seem to fit. Here's the summary:

On the verdant world of Irya, semi‑feline artisans known as the Sithi live among aerial bowers suspended in the branches of the colossal Tree of Winds.
Their culture revolves around song‑cloths—iridescent silks that hum in the constant breezes, tuned to specific tonal patterns.
The most prized is the Azure Weave, spun only by the subterranean Spinner‑Being, a blind creature that extrudes resonant filaments.
When outsiders (a trading species) steal the Spinner’s azure threads, the harmonic winds turn chaotic and storms ravage the canopy cities.
The young weaver Seri of the Skybowers journeys below to atone, discovering that the Spinner is sentient and has woven the planet’s literal harmony.

I'm desperate to know the name and author and would love to find a copy

Is this stuff you remember, which you needed AI to word for you for some reason? If you are blindingly trusting that AI has gotten details correct which you don't specifically remember, it is far more likely that AI has made up something that does not exist and which you will never find.

What I remembered was cat-like creatures that I thought were called Sithi that had singing cloths made of a fibre spun by a creature that lived under a tree. The azure cloth was very special. I also remembered the sithi lived in bowers.
The summary AI has come up with is correct. I never mentioned the traders, the outsiders, but when AI brought it up I remembered their part in the story. I'm not sure if the name Seri of the Skybowers is correct, but it seems right. The story did go that way, one young sithi going underground to get more azure song--cloth from the spinner. The spinner was definitely blind, though I did not supply that information to the AI. The AI guessed incorrectly at the author's name and the title as far as I can tell, but where it has filled in blanks on the plot summary it is pretty spot on in matching my memory.
The AI mentioned the collector's notes that it had pieced this together from thought the book was a "lost" Mildred Braxon book, but I can find no evidence of this.

Maybe something by Andre Norton? I'm not familiar with most of her vast bibliography, but cats are a recurring theme.

Starsilk by Sydney Van Scyoc. It's the third of her Sunstone trilogy. The summary isn't totally accurate though.
The first two books are set on the planet Brakrath, which has a short summer and long winter; during which the inhabitants literally hibernate. In Starsilk, a girl from the planet travels to the Sithi world, looking for news of an ancestor. She finds a white silk imprinted with his consciousness, and brings to back to Brakrath. She meets a Sithi and a bluesilk, but doesn't steal it or cause any storms.https://www.fantasticfiction.com/v/sydney-j-van-scyoc/starsilk.htm

touchstones:
Starsilk by Sydney J. Van Scyoc (collected in Daughters of the Sunstone)

Thank you! I've definitely read that series. I recognize the cover you've linked to and the covers of the other two in the series, though it seems those particular covers are less common. I found the book on archive.org and had a quick browse and it does seem like you've hit the nail on the head. I don't remember storms, just the outsiders in the story. The storms and stealing is something the AI supplied. Thank you very much.

>6 DisassemblyOfReason: thank you. Pretty sure that's it